I have a 1990 Sentra Automatic. I have been reading some other threads on what could be wrong, but I can't make much sense of it. The fuel filter is a year old, the spark plugs and wires are about 2 months old, I have a new alternator, new starter switch, a new starter, and a new battery. Yet still, when I start my car up. it will run for a few seconds, and then die. I must do this a few times with my foot on the gas to keep it from dying again. And still when I shift into reverse or drive, it dies. Also, when I do get it going, sometimes, my RPMs will fluctuate spontaniously, High-Low-Hig-Low, and the car lurches from the change in power. I need a basic explanation on what's wrong, and how to fix it... I want to do it myself as I am a student, and know a little something about cars. So any pictures or step-by-steps y'all could post would be much appreciated.